This invention relates generally to methods and apparatus for packaging food products in two distinctly different atmospheric conditions.
For some time now, it has been appreciated that there are considerable advantages to be achieved from a package which can accommodate two distinctly different packaging concerns. The first of those concerns is to extend the shelf life of the product by reducing its exposure to oxygen. This means that the product is advantageously isolated from oxygen exposure from the time the food product is packaged until just before it is ready to go on sale. By avoiding oxygen exposure during this period, the shelf life of the package can be increased because exposure to oxygen is what begins the degradation of the food product. Thus, the product can be transported from a remote location to a point of sale over a number of days without endangering the product. The product's useful life is determined primarily from the time that oxygen exposure is initiated.
The second packaging concern relates to the situation where, particularly with respect to red meat, it is advantageous to expose the meat to oxygen prior to sale. The oxygen exposure causes the meat to turn bright red from its unexposed purple color. As mentioned above, oxygen exposure begins the degradation and thus, it is advantageous to forestall the oxygen exposure to the greatest possible extent.
A number of techniques have been proposed to allow the package to undergo two distinct states. One procedure involves a package which has a pair of films, one of which is permeable and the other of which is impermeable. When the impermeable film is removed, the permeable film remains. Oxygen flow from the atmosphere through the permeable film enables blooming of the food product, at least in the case of red meat.
Thus, there would be a considerable demand for a product which efficiently allows a package to experience two distinct packaging state with two distinctly different packaging environments.